PROG (Version 0.7) is a reasonable program that provides all that is necessary
(and a little more) for easy straight-forward programming of EPROMs. The
ability to load and save data to/from various files is a useful feature, as is
the limited editing. Those requiring more extensive editing features (such as
block moves or block fills) will have to resort to loading the data file under
a debugger such as Gemdebug, ZSID, or DDT and using their facilities. The
display option is useful as it lets you visually check the buffer contents
before programming. (This ensures that you have loaded the correct file and
that it does contain what you think it does.)
The only obvious omission is the ability to program a limited range of
addresses within the EPROM. At the moment it is a case of ‘all or nothing’.
(Mind you the software does not bother to program any byte that is 0FFh, so
this can be got around in a roundabout way although the ‘verify’ code may
In general the ESCape key acts as an abort key to return you to the main menu.
However this feature does not work during programming, and there is no visual
echo of the progress of the programming operation. I assume this is to reduce
the display/polling overhead that would otherwise occur and cause an increase
in the overall programming time, but it is a pity that it has been omitted.
Perhaps this will be changed in a later release of the software.
It is nice to see the programmer as a separate unit rather than an 80-BUS
card. If anyone has ever used a system where the programmer was on a plug-in
card they will know the frustrations of that approach. (You have to work with
the lid off the computer and have to juggle the cards around to get the EPROM
card into a position where you can actually get EPROMs into and out of the
socket – The socket is more often than not vertical, and when you flick the
lever to release the EPROM it often falls out into the guts of the computer!)
If you do not have a disk-based system, or want some unusual feature in your
control software, the file PROGINIT.MAC contains the low level drivers that
form part of PROG. If you are writing software to be ‘PROM’ed then it is
likely that you should be able to add your own control routine to PROGINIT
although you will have to do a certain amount of detective work to work out
exactly what to do. PROGINIT.MAC – I think it should actually be PROGINIT.C
judging by the comments at the start – starts off with a section of comments
that tells you what bits where control what. (e.g. Bit X of the control latch
selects a Vcc of 5v or 6v, set bit Y for 2lv programming voltage, etc.) What
it leaves you to work out for yourself are the bit. combinations required for
the various EPROM types.
The Gemini EPROM programmer is fairly obviously targeted on Gemini Galaxy and
Quantum users, but any Multiboard/Gemini/Nascom owner running CP/M should be
able to use the package without any difficulty. (N.B. The screen display of
PROG.COM is obviously orientated towards the Gemini
disk systems will have to write some of the support software themselves.
The price of #150 (+VAT) seems a little on the high side to me, but it is
neatly packaged (unlike the earlier Bits & PC’s programmer which came as a
bare board) and it definitely does work.